May 6, 2021

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A world-wide environmental crisis 42,000 several years ago

Reversing the discipline

Do terrestrial geomagnetic field reversals have an impact on Earth’s weather? Cooper et al. created a exactly dated radiocarbon report close to the time of the Laschamps geomagnetic reversal about 41,000 several years in the past from the rings of New Zealand swamp kauri trees. This file reveals a sizeable boost in the carbon-14 content of the atmosphere culminating throughout the interval of weakening magnetic field strength previous the polarity swap. The authors modeled the outcomes of this function and concluded that the geomagnetic industry bare minimum brought on substantial adjustments in atmospheric ozone concentration that drove synchronous world weather and environmental shifts.

Science, this concern p. 811

Abstract

Geological archives file many reversals of Earth’s magnetic poles, but the world-wide impacts of these functions, if any, continue being unclear. Uncertain radiocarbon calibration has limited investigation of the potential outcomes of the final major magnetic inversion, recognized as the Laschamps Excursion [41 to 42 thousand years ago (ka)]. We use ancient New Zealand kauri trees (Agathis australis) to establish a in-depth file of atmospheric radiocarbon ranges across the Laschamps Excursion. We precisely characterize the geomagnetic reversal and accomplish world chemistry-climate modeling and comprehensive radiocarbon dating of paleoenvironmental data to investigate impacts. We come across that geomagnetic field minima ~42 ka, in mixture with Grand Photo voltaic Minima, triggered sizeable adjustments in atmospheric ozone concentration and circulation, driving synchronous world-wide weather shifts that brought on major environmental variations, extinction gatherings, and transformations in the archaeological document.